I got this "problem" only on a local terminal via HDMI-Monitor and USB-keyboard and not via ssh/putty. The last one where I did see the keyboard problem was on my Sunvell T95K Pro (TV Box) unser armbian.   I also did use pkg-reconfigure keyboard-configuration, but got US-Keyboard also after a reboot.   I dont know any more if I did try it later via armbian-config, but some reboots/apt-updates later I did get a german keyboard without doing anything else.